The present invention relates to a body filling material or agent for medical purpose.
A body filler is used for various medical purposes, such as cosmetic surgery for stretching facial wrinkles, breast implantation, treatment for incontinent by narrowing urethra, by injecting collagen, and so on. Also, an embolic agent is used for filling a void inside a body, such as treatment of aneurysm in brain and so on. The body filling agent in the present invention is used as the body filler and embolic agent.
One of the most common body fillers used in a medical field is a collagen well known in the art. The collagen is produced from animals, and is very biocompatible with a human body. However, the human body gradually absorbs the collagen, for example in about 6 to 12 months, when applied to the human body. Therefore, if the collagen is used as a permanent body filler, repeated applications of the collagen are required.
Another well-known body filler is silicone. However, due to the problem occurred in the breast implantation, silicone is not used commonly any longer.
It is very important that the body filler is biocompatible for a long term implantation and very easy in application, such as having fluidity. Also, the body filler should not be absorbed into the body too much even if it is absorbed. Preferably, an amount of the body filler to be absorbed into the body is controllable depending on a purpose of use.
Thus, it is desired to provide a body filling agent including a body filler and embolic agent for medical purpose, which is compatible with a human body and can remain at a predetermined position of the body for a long time.
Accordingly, an object of the invention is to provide a body filling agent which is biocompatible to a human body and is used aa a body filler and an embolic agent.
Another object of the invention is to provide a body filling agent as stated above, wherein a desired amount of the body filling agent can remain at a desired position applied in the body for a long time.
Further objects and advantages of the invention will be apparent from the following description of the invention.
A body filling agent of the invention is formed of a collagen, and at least one kind of implantable particles selected from a group consisting of implantable polymer and pericardium. A mixture of the collagen and the implantable particles form the body filling agent to be deposited in a human body.
The collagen has been known and widely accepted as a filler though the collagen is absorbed into a body in a certain period of time and forms, when mixed with a blood, a blood clot for preventing bleeding. In the invention, the collagen known in the art is used in a powder, fiber or gel form. In view of handling, the collagen in a powder form is used.
The implantable particles used in the present invention are implantable polymer particles, and/or pericardium particles. Namely, the polymer particles and/or pericardium particles in a powder or fibrous form are used.
The implantable polymer may be polyester, urethan and polytetrafluoroethylene. The polymer has been used to form a vein graft to be implanted into the body. In one example, fibers are formed from the polymer and the vein graft is made by weaving the fibers of the polymer. In another example, the polymer is foamed, such as expanded polytetrafluoroethylene, to have an elongated and flexible tube.
In the invention, the polymer used for forming an article for implantation is used. The polymer is processed to form a powder or fiber to be mixed with the collagen. The powder and fibers should have a size to be injectable by an injector.
The pericardium is a membrane tissue surrounding a heart and available from animals, such as pig and cow. The pericardium has been used for implantation, such as soft heart valves and ligaments, and is generally regarded as being compatible with a human body. However, if the pericardium powder is only implanted or applied into a human body as a filler, the pericardium powder is not accepted.
It has been found that although the polymer particles and pericardium particles are not accepted in the human body as body fillers by themselves, the mixture of the collagen and the polymer particles and/or pericardium particles is not rejected and accepted by the human body. Thus, the present invention has been made.
When the mixture of the collagen, and the polymer particles and/or pericardium particles is implanted or applied into the human body, the collagen is gradually absorbed into the body, but the polymer particles and/or pericardium particles remain and accepted in the body. Thus, the mixture can be used as a permanent body filling agent.
The body filling agent is preferably mixed with a suspending liquid, i.e. water, for suspending the mixture of the collagen and the polymer particles and/or pericardium particles. As a result, the body filling agent with the suspending liquid can be injected into the body by an injector, so that the implantation or application of the body filling agent can be made easily.
In preparing the body filling agent of the invention, the polymer as explained above is processed to form a powder or fibers. In case of using the pericardium, the pericardium is obtained from an animal, such as pig or cow, and the pericardium is crushed into a fine powder. The pericardium in the fibrous form may be used. The polymer and/or pericardium particles, i.e. powder or fibers, are mixed with a collagen, i.e. powder, fiber or gel form. When the body filling agent in a fluid form is required, suitable liquid, such as water, is added to the mixture, so that the fluid containing the polymer and/or pericardium particles, and collagen can be injected into a desired place, such as under skin or in muscle by an injector.